There's a little thing John Noble does that I didn't notice the first time through. Whenever someone asks Walter something connected to Peter's childhood or his past, Walter will often look at Peter before he answers. Sometimes it's barely a glance. Knowing where that story goes makes those moments feel completely different because it looks less like Walter is remembering and more like he's checking what Peter knows.

On my rewatch, currently by season 2. I always find it amazing how the few seconds we see Walter reunited with his whole Brain (s2e10), he shows his real past self. An arrogant, agressive and potent scientist.

So different from the humble, fuzzy and addled Walter Bishop we get to know in the series.

In the same episode Ollivia says: I think getting crazy made him a better person.

A lot of us binge watch shows now, I say we pickup the REAL story from when season 3 left off - and say season 4 & 5 were from the observer POV as a cautionary tale to the rigid militant group.